Artificial filament



Fatented Apr. 30,: E935 MNHTED STATES ARTIFICIAL FILAMENT CamilleDreyfus, New York, N. Y., and William Whitehead, Cumberland, Md.,assignors to Gelanese Corporation of tion of Delaware America, acorporan Drawing. Application November 18, 1930, Serial No. 496,562

6 Claims.

This invention relates to the preparation of artificial filaments, yarnsand the like and re lates more particularly to the preparation of yarnshaving apleasing appearance and improved textile properties.

An object of our invention is to prepare artificial filaments havingimproved appearance and other desirable properties 'and which contain atitanic acid. Other objects of our invention will appear from thefollowing detailed description.

It has been previously proposed to incorporate inorganic pigment-likematerial in artificial yarn to subdue the lustre and increase theopacity thereof. In commercial processes involving the use of suchpigments, many considerations enter so that the choice of a commerciallysuitable pigment is quite dificult. We have found that such pigment mustgrind easily, must have good covering power, must have a low specificgravity so that it does not tend to separate out readily from thespinning solution to which it is added, and preferably should be oflight color. We have found that the titanic acids meet theserequirements.

In accordance with our invention we prepare artificial filamentscontaining cellulosic materials which have improved properties byincorporating therein a finely divided titanic acid.

The filaments made or treated in accordance with this invention may beof low fine denier which are associated together to form yarn, or thefilaments may be, heavier such as bristles, artificialhorsehair andstraw. Such filaments may be of the reconstituted cellulose type formedby the Chardonnet or cuprammonium process, but this invention isparticularly applicable to filaments containing organic derivatives ofcellulose such as organic esters of cellulose and cellulose ethers.Examples of such organic esters of cellulose are cellulose acetate,cellulose formate, cellulose propionate and cellulose butyrate, whileexamples of cellulose ethers are ethyl cellulose, methyl cellulose andbenzyl cellulose. The filaments containing the organic derivative ofcellulose may be prepared by dissolving the organic derivative in avolatile solvent such as acetone and extruding such solutions throughfine orifices into an evaporative atmosphere, as in dry spinning, orinto a precipitating bath, as in wet Spinning.

As stated, we incorporate in the filaments a finely divided titanicacid. While any suitable titanic acid may be used, we-prefer to use thetitanic acid having the formula HzTiOa, which may be formed by adding anaqueous solution of sodium carbonate to an aqueous solution of potassiumtitanium oxalate and then washing and drying the precipitate. Thesetitanic acids are white in color and have remarkably high coveringpower. Moreover, titanic acid is much softer 5 than titanium dioxide andtherefore filaments or yarns containing titanic acid do not tend to cutmachinery parts, such as guides, knitting needles, etc: as readily asfilaments or yarns containing a like amount of titanium dioxide.

In one form of our invention, the titanic acid is incorporated in thedope or spinning solution containing the cellulose compound. Generallythe amount of titanic acid added is from 0.1 to 10% of the weight of thecellulose compound present in the finished yarn. The titanic acid ispreferably in very fine form, the particles having a diameter of lessthan 0.1 to 5 microns and preferably less than 1 or 2 microns forincreased covering power. This fine size may be attained 20 by grindingthe titanic acid either with water or part of the spinning solution orthe solvent used in the spinning solution in a ball mill'or colloidmill. The ground material is then added to the solution of thederivative of cellulose and to which mayalso be added diethylene glycol,heavy white mineral oil, olive oil, castor oil or other oils. Thespinning solution containing the pigment is then preferably thoroughlymixed and subjected to the usual filtration before spinning. However theaddition of the titanic acid to the spinning'dope at any stage of thefiltration process or even after completion of filtration is notexcluded.

In another form of our invention, the finely divided titantic acid isincorporated in the yarns or filaments by treating such yarns orfilaments after their formation either'in the form, of hanks or in theform of woven or knitted fabric with a suspension of titanic acid in thepresence of a swelling or penetrating agent for the cellulosic materialof which such filaments are composed which causes the titanic acid tobecome disseminated throughout the filaments. Thus if the filaments aremade of cellulose acetate, the swelling agent employed may be an aqueoussolution of acetone, acetic acid, thiocyanates of sodium, potassium orammonium, diacetone alcohol or any other suitable swelling agent.

Filaments or yarns made in accordance with this invention have a subduedlustre and increased opacity and covering power, the amount of whichdepends upon the fineness of the size of the titanic acid particles andthe amount employed. Yarns made in accordance with this invention havehighly improved textile properties,

as is shown by. the fact that they can be knitted to form circular knitor warp knit fabrics having many wales and courses and which are free ofdistortions and pin holes. Moreover such yarns may be woven to formfabrics which arefree of warp streaks and weft bars.

Yarns prepared by our method may be wound and twisted more readily andform cones or other packages which do not tend to collapse. Heavierfilaments such as bristles, straw and the like when made in accordancewith this invention have improved knotting properties.

In order further to illustrate our invention, but without being limitedthereto, the following specific example is given.

Example One (1) part by weight of an acetone soluble cellulose acetateis dissolved in three (3) parts by weight of acetone and to this isadded one hundredth (0.01) part by weight of titanic acid (HzTiOa) in asmall amount of water or acetone preferably containing celluloseacetate. This dispersion maybe obtained by grinding the titanic acidwith the liquid, to whichgranules or fibers of If desired olive oil or'diethylene glycolor a mixture of the two, in amounts of 1 to 5% of theweight of the cellulose acetate present may be added to the solution ofthe cellulose acetate prior to spinning. Also instead of adding thefinely divided titanic acid to the spinning solution before thefiltration, it may be added after such filtration.

It is to be understood that the foregoing description is given merely byway of illustration and that many variations may be made therein withoutdeparting from the spirit of our invention.

Having described our invention, what we desire and claim to secure byLetters Patent is:

1. Artificial products containing a finely divided titanic acid.

2. Artificial products containing an organic derivative of cellulose anda finely divided titanic acid.

3. Artificial filaments or yarn containing cellulose acetate and afinely divided titanic acid.

4. Artificial filaments or yarn containing finely divided particles of atitanic acid having a. diameter of less than 5 microns.

5. Artificial filaments or yarn containing cellulose acetate and finelydivided particles of a titanic acid having a diameter of less than 2microns.

1 6. Artificial filaments or yarns containing an organic derivative ofcellulose, an oil and a finely divided titanic acid.

CAMILLE DREYFUS. WILLIAM WHITEHEAD.

